Methods for manufacturing an electric machine

ABSTRACT

A method for manufacturing an electrical machine includes printing a stator core; printing a first part of a stator winding; coupling the first part of the stator winding to the stator core; printing a second part of the stator winding onto the first part of the stator winding to form a stator assembly; printing a first part of a rotor shaft; printing a rotor core onto the first part of the rotor shaft; printing a second part of the rotor shaft onto the rotor core; printing a first part of a rotor winding; coupling the first part of the rotor winding to the rotor core; and printing a second part of the rotor winding onto the first part of the rotor winding to form a rotor assembly.

PRIORITY CLAIM

The present application claims the benefit of priority of U.S.Provisional Patent Application No. 62/445,864, entitled “PRINTEDELECTRICAL MACHINERY,” filed Jan. 13, 2017, which is incorporated hereinby reference for all purposes.

FIELD

The present subject matter relates generally to additively manufacturedcomponents, and more particularly, to electrical machinery and methodsfor manufacturing electrical machinery.

BACKGROUND

Electrical machinery, such as generators, motors, motor/generators,starter/generators, and other electrical machinery can be used for avariety of purposes. An electrical machine can include a stator and arotor. The rotor can be rotated relative to the stator to generateelectrical energy and/or can be rotated relative to the stator as aresult of changing magnetic fields induced in windings of the stator.

Typical methods of manufacturing an electrical machine can include, forinstance, manufacturing a stator or other component by stacking oxidizedlamination sheets to form a core, winding coils made of insulated wire,inserting slot liners and coils into slots of the core, sliding slotwedges at the top of a slot, forming end turns, and varnishing thestator and/or rotor assembly.

BRIEF DESCRIPTION

Aspects and advantages of embodiments of the present disclosure will beset forth in part in the following description, or may be learned fromthe description, or may be learned through practice of the embodiments.

In an example embodiment, a method for manufacturing an electricalmachine includes printing a stator core. The method also includesprinting a first part of a stator winding. In addition, the methodincludes coupling the first part of the stator winding to the statorcore. The method also includes printing a second part of the statorwinding onto the first part of the stator winding to form a statorassembly. In addition, the method includes printing a first part of arotor shaft. The method also includes printing a rotor core onto thefirst part of the rotor shaft. In addition, the method includes printinga second part of the rotor shaft onto the rotor core. The method alsoincludes printing a first part of a rotor winding. In addition, themethod includes coupling the first part of the rotor winding to therotor core. The method also includes printing a second part of the rotorwinding onto the first part of the rotor winding to form a rotorassembly. In particular, coupling the first part of the stator windingto the stator core precedes printing the second part of the statorwinding onto the first part of the stator winding. In addition, couplingthe first part of the rotor winding to the rotor core precedes printingthe second part of the rotor winding onto the first part of the statorwinding.

In some implementations, the method includes printing a housing defininga cavity.

In some implementations, printing the stator core comprises printing afirst projection, wherein printing the first part of the stator windingcomprises printing a second projection, and wherein the first projectioncontacts the second projection when the first part of the stator windingis coupled to the stator core.

In some implementations, the method includes applying a varnish or epoxyto the stator assembly; removing the first projection from the statorcore after applying the varnish or epoxy; and removing the secondprojection from the first part of the stator winding after applying thevarnish or epoxy.

In some implementations, applying the varnish or epoxy precedes printingthe first part of the rotor shaft.

In some implementations, removing the first projection from the statorcore precedes printing the first part of the rotor shaft, and whereinremoving the second projection from the first part of the stator windingprecedes printing the first part of the rotor shaft.

In some implementations, printing the rotor core comprises printing afirst projection, wherein printing the first part of the rotor windingcomprises printing a second projection, and wherein the first projectioncontacts the second projection when the first part of the rotor windingis coupled to the rotor core.

In some implementations, the method includes applying a varnish or epoxyto the rotor assembly; removing the first projection from the rotor coreafter applying the varnish or epoxy; and removing the second projectionfrom the first part of the rotor winding after applying the varnish orepoxy.

In some implementations, printing the first part of the stator windingcomprises printing first end turns and a plurality of coils, and whereinprinting the second part of the stator winding comprises printing secondend turns.

In some implementations, printing the plurality of coils comprisesprinting at least one wire.

In another example embodiment, a method for manufacturing an electricalmachine includes printing, by a three-dimensional (3D) printing process,a stator core. The method also includes printing, by the 3D printingprocess, a first part of a stator winding. In addition, the methodincludes coupling the first part of the stator winding to the statorcore. After coupling the first part of the stator winding to the statorcore, the method includes printing, by the 3D printing process, a secondpart of the stator winding onto the first part of the stator winding toform a stator assembly. The method also includes printing, by the 3Dprinting process, a rotor core. In addition, the method includesprinting, by the 3D printing process, a first part of a rotor shaft ontoa first end of the rotor core. The method also includes printing, by the3D printing process, a second part of the rotor shaft onto a second endof the rotor core. In addition, the method includes printing, by the 3Dprinting process, a first part of a rotor winding. The method alsoincludes coupling the first part of the rotor winding to the rotor core.After coupling the first part of the rotor winding to the rotor core,the method includes printing, by the 3D printing process, a second partof the rotor winding onto the first part of the rotor winding to form arotor assembly. In particular, the 3D printing process comprises fusingmetal using laser energy or heat.

In some implementations, the method includes printing, by the 3Dprinting process, a housing defining a cavity.

In some implementations, printing the stator core comprises printing, bythe 3D printing process, a first projection, wherein printing the firstpart of the stator winding comprises printing, by the 3D printingprocess, a second projection, and wherein the first projection contactsthe second projection when coupling the first part of the stator windingto the stator core.

In some implementations, the method includes applying a varnish or epoxyto the stator assembly; removing the first projection from the statorcore after applying the varnish or epoxy; and removing the secondprojection from the first part of the stator winding after applying thevarnish or epoxy.

In some implementations, applying the varnish or epoxy occurs beforeprinting the rotor core.

In some implementations, removing the first projection from the statorcore precedes printing the rotor core, and wherein removing the secondprojection from the first part of the stator winding precedes printingthe rotor core.

In some implementations, printing the rotor core comprises printing, bythe 3D printing process, at least one damp bar, and printing, by the 3Dprinting process, a damp ring after printing the at least one damp bar.

In some implementations, printing the first part of the stator windingcomprises printing first end turns and a plurality of coils, and whereinprinting the second part of the stator winding comprises printing secondend turns.

In some implementations, coupling the first part of the stator windingto the stator core comprises inserting each coil of the plurality ofcoils into one slot of a plurality of slots defined by the stator core.

In some implementations, printing the plurality of coils comprisesprinting at least one wire.

These and other features, aspects and advantages of various embodimentswill become better understood with reference to the followingdescription and appended claims. The accompanying drawings, which areincorporated in and constitute a part of this specification, illustrateembodiments of the present disclosure and, together with thedescription, serve to explain the related principles.

BRIEF DESCRIPTION OF THE DRAWINGS

Detailed discussion of embodiments directed to one of ordinary skill inthe art are set forth in the specification, which makes reference to theappended figures, in which:

FIG. 1 depicts a flow diagram of an example method for manufacturing anelectrical machine according to example embodiments of the presentdisclosure;

FIG. 2 depicts a flow diagram of an example method of manufacturing astator assembly according to example embodiments of the presentdisclosure;

FIG. 3 depicts an example lamination sheet and spacer(s) for printing astator core according to example embodiments of the present disclosure;

FIG. 4 depicts an example stator core printed according to exampleembodiments of the present disclosure;

FIG. 5 depicts an example first part of a stator winding printedaccording to example embodiments of the present disclosure;

FIG. 6 depicts an example first part of a stator winding assembled witha stator core according to example embodiments of the presentdisclosure;

FIG. 7 depicts an example first projection of a stator core contactingan example second projection of a first part of a stator windingaccording to example embodiments of the present disclosure;

FIG. 8 depicts an example second part of a stator winding printed onto afirst part of the stator winding according to example embodiments of thepresent disclosure;

FIG. 9 depicts an example flow diagram of manufacturing a rotor assemblyaccording to example embodiments of the present disclosure;

FIG. 10 depicts a portion of rotor core according to example embodimentsof the present disclosure;

FIG. 11 depicts an example lamination sheet and spacer(s) for printing arotor core according to example embodiments of the present disclosure;

FIG. 12 depicts a rotor core printed according to example embodiments ofthe present disclosure;

FIG. 13 depicts a first part of a rotor winding printed according toexample embodiments of the present disclosure;

FIG. 14 depicts an example first part of a rotor winding assembled witha rotor core according to example embodiments of the present disclosure;

FIG. 15 depicts an example first projection of a rotor core contactingan example second projection of a first part of a rotor windingaccording to example embodiments of the present disclosure;

FIG. 16 depicts an example second part of a rotor winding printed onto afirst part of the rotor winding according to example embodiments of thepresent disclosure;

FIG. 17 depicts a rotor assembly printed according to exampleembodiments of the present disclosure;

FIG. 18 depicts a cross-sectional view of a rotor core printed accordingto example embodiments of the present disclosure;

FIG. 19 depicts a rotor core printed according to example embodiments ofthe present disclosure;

FIG. 20 depicts a plurality of damp bars coupled to a rotor coreaccording to example embodiments of the present disclosure;

FIG. 21 depicts a damp ring coupled to the rotor core of FIG. 18according to example embodiments of the present disclosure;

FIG. 22 depicts a first part of a rotor shaft printed onto a rotor coreaccording to example embodiments of the present disclosure;

FIG. 23 depicts a second part of a rotor shaft printed onto a rotor coreaccording to example embodiments of the present disclosure;

FIG. 24 depicts a flow diagram of an example method for manufacturing arotor assembly according to example embodiments of the presentdisclosure;

FIG. 25 depicts an example housing with an integrated cooling jacketprinted according to example embodiments of the present disclosure;

FIG. 26 depict a flow diagram of an example method for assembly anelectrical machine according to example embodiments of the presentdisclosure;

FIG. 27 depict a flow diagram of an example method for assembling anelectrical machine according to example embodiments of the presentdisclosure

FIG. 28 depicts a cross-sectional, perspective view of an example statorhousing according to example embodiments of the present disclosure;

FIG. 29 depicts a perspective view of an example stator housingaccording to example embodiments of the present disclosure;

FIG. 30 depicts a cross-sectional, perspective view of an example statorhousing according to example embodiments of the present disclosure;

FIG. 31 depicts a cross-sectional, perspective view of an example statorhousing according to example embodiments of the present disclosure; and

FIG. 32 depicts a perspective view of an example stator housingaccording to example embodiments of the present disclosure;

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments, one or moreexamples of which are illustrated in the drawings. Each example isprovided by way of explanation of the embodiments, not limitation of theembodiments. In fact, it will be apparent to those skilled in the artthat various modifications and variations can be made in the presentdisclosure without departing from the scope or spirit of the invention.For instance, features illustrated or described as part of oneembodiment can be used with another embodiment to yield a still furtherembodiment. Thus, it is intended that the present disclosure covers suchmodifications and variations as come within the scope of the appendedclaims and their equivalents.

As used in the specification and the appended claims, the singular forms“a,” “an,” and “the” include plural referents unless the context clearlydictates otherwise. The use of the term “about” in conjunction with anumerical value refers to within 25% of the stated amount.

Example aspects of the present disclosure are directed to additivelymanufactured or “printed” components of electrical machinery (e.g.,rotary electrical machines) and/or to methods for manufacturing thesame. As used herein, use of the term “printed” or “printing” refers to,for instance, manufacturing processes wherein successive layers ofmaterial(s) are provided on each other to “build-up”, layer-by-layer, athree-dimensional component. Example manufacturing processes forprinting metal components of an electrical machine will be discussed indetail below.

The electrical machinery can be manufactured, for instance, by printinga stator assembly according to example aspects of the presentdisclosure, printing a rotor assembly according to example aspects ofthe present disclosure, and printing a housing (including the coolingjacket and/or end caps) according to example embodiments of the presentdisclosure. The components can then be assembled together to form anelectrical machine. Example electrical machines that can be assembledaccording to example embodiments of the present disclosure can includegenerators, motors, motor/generators, starter/generators, etc. In someembodiments, the electrical machine can be air cooled. In someembodiments, the electrical machine can be liquid cooled. In someembodiments, the electrical machine can be a wet cavity machine, a drycavity machine, and/or wet/dry combination.

In example embodiments, a method for manufacturing a stator assembly foran electrical machine can include: printing a stator core of anelectrical machine; printing a first part of a stator winding to becoupled to the stator core, coupling the first part of the statorwinding to the stator core, and printing the second part of statorwinding onto the first part of the stator winding to form the statorassembly. A varnish or epoxy can then be applied to the stator assembly.In particular, the varnish or epoxy can be potted (e.g., with epoxy) orelectrophoretic deposited. In this way, the lamination to lamination,ground insulation, turn-to-turn insulation, and phase-to-phaseinsulation can be established. As will be discussed below in moredetail, a first projection printed as part of the stator core and asecond projection as part of the first part of the stator winding can beremoved after the varnish or epoxy has been applied to the statorassembly.

In some embodiments, a stator core can be printed by printing laminationsheets with printed spacers between the lamination sheets. The spacerscan be small enough to make eddy current losses negligible in the statorcore. In some embodiments, a higher resistivity metal relative to themetal used for the lamination sheets may be used for the spacers tofurther reduce eddy current losses cause by space between laminationsheets. A desired slot skew can be printed along with the laminationsheets. A slot wedge can be printed along with the lamination sheets.Additional temporary shapes (e.g., first projection) can be added to thelamination sheets along with the spacers, and these additions along withthe spacers can be removed after varnishing, potting, depositing etc.

In some embodiments, a stator winding can be printed in two parts. Morespecifically, a first part can be printed that includes bottom end turnsand a plurality of coils for insertion into slots defined by the statorcore. In some embodiments, the second projection can be printed as partof the first part of the winding. Then, when coupling the first part ofthe stator winding to the stator core, the first projection can contactthe second projection. In this way, the first and second projections canensure space between phases, space between turns, space between coilsand slots, space between end turns and core face, etc. Once the firstpart of the stator winding is coupled to the stator core, a second partof the winding (e.g., the top end turns) can be printed onto the firstpart of the stator winding to form the stator assembly. In exampleembodiments, the wire for the windings and other components can beprinted in solid wire, multi-strain wire, Litz wire or hollow wire.

After printing the second part of the stator winding, a varnish or epoxycan be applied to the stator assembly. In an example embodiment,applying the varnish or epoxy can include potting the epoxy onto thestator assembly. Alternatively, applying the varnish or epoxy caninclude electrophoretically depositing the epoxy onto the statorassembly. After applying the varnish or epoxy, spaces in the statorassembly can be filled with insulation. In addition, the firstprojection can be removed from the stator core, and the secondprojection can be removed from the first part of the stator winding.

In example embodiments, the rotor shaft and the rotor core can beprinted as an integrated piece. Optionally, cooling tubes can beincluded as part of the rotor core. The additional cooling tubes canenhance heating dissipation capability of the rotor. In someembodiments, the cooling tubes can be printed as part of the coreinstead of being manufactured as separate pieces from the core andwelded on the shaft.

For instance, in some embodiments, a first part of a rotor shaft can beprinted layer by layer until the first part of the rotor shaft reaches adesired height. The first part of the rotor shaft can be printed using arelatively low cost material relative to a material used to print therotor core. After printing the first part of the rotor shaft, the rotorcore can then be printed as a plurality of lamination layers separatedby spacers. In example embodiments, the shaft area passing through therotor core can be printed as solid layers. Once the rotor core has beenprinted, a second part of the rotor shaft can be printed layer by layeruntil it reaches a desired height. The second part of the rotor shaftcan be printed using the same material as the first part of the rotorshaft. In some embodiments, at least one damp bar can be inserted intoone of a plurality of slots defined by the rotor core. Alternatively oradditionally, at least one damp ring can be printed and coupled to atleast one end of the rotor core.

In some embodiments, a winding for the rotor can be printed in twoparts. More specifically, a first part of the rotor winding can beprinted that includes bottom end turns and the coils for insertion intothe rotor core. In some embodiments, a first projection printed as partof the rotor core can contact a second projection printed as part of thefirst part of the rotor winding. More specifically, when the first partof the rotor winding is coupled to the rotor core, the first projectioncan contact the second projection to ensure space between turn-to-turn,space between coils and slots, space between end turns and core face,etc. Once the first part of the rotor winding is coupled to the rotorcore, a second part of the winding (e.g., the top end turns) can beprinted onto the first part of the winding to form the rotor assembly.

After printing the second part of the rotor winding, a varnish or epoxycan be applied to the rotor assembly. In an example embodiment, applyingthe varnish or epoxy can include potting the epoxy onto the rotorassembly. Alternatively, applying the varnish or epoxy can includeelectrophoretically depositing the epoxy onto the rotor assembly. Afterapplying the varnish or epoxy, spaces in the rotor assembly can befilled with insulation. In addition, the first projection can be removedfrom the rotor core and the second projection can be removed from thefirst part of the rotor winding. Still further, all associatedaccessories of the rotor assembly (e.g., end caps, retaining rings,etc.) can be coupled to at least one of the rotor core and rotor shaft.

In example embodiments, a housing for the electrical machine can beprinted layer by layer. In some embodiments, the housing can be printedlayer-by-layer perpendicular to the centerline that goes through twobearing centers. In some embodiments, the housing can include a coolingjacket that is integral with the housing. In some embodiments, thehousing can be integral with the stator core. In addition, a coolingjacket can be integral with the housing that is integral with the statorcore. Once the stator, rotor, and housing have been manufacturedaccording to example embodiments of the present disclosure, thecomponents can be assembled to form an electrical machine.

For example, one example embodiment of the present disclosure isdirected to a method of manufacturing an electrical machine having amain, an exciter, and a permanent magnet generator (PMG) integrated aspart of single electrical machine. The present example is provided forpurposes of illustration and discussion. Those of ordinary skill in theart, using the disclosures provided herein, will understand that theexample processes and techniques discussed herein can be used formanufacturing other electrical machines without deviating from the scopeof the present disclosure.

The various components of the electrical machine can be printedaccording to example embodiments of the present disclosure. For examplethe main stator, the exciter stator, and the PMG stator can all beprinted according to example aspects of the present disclosure. Thestators and the exciter armature can then be varnished, potted, ordeposited.

A main rotor including rotor core (with winding) and rotor shaft can beprinted. The main rotor can be varnished, potted, or deposited. Inaddition, other components (e.g., end cap, retaining rings, etc.) can beadded. The exciter rotor can be printed according to example embodimentsof the present disclosure. The PMG rotor can be printed according toexample aspects with the present disclosure with slots for permanentmagnets. The exciter rotor can be varnished. Various componentsassociated with the rotor can then be assembled, such as a rotatingrectifier, bearings, seals, etc. Electrical connections to thecomponents of the rotor can be added.

A housing for the electrical machine can be printed. In someembodiments, air cooling fins and/or a liquid cooling jacket can beprinted as part of the housing. End caps for the electrical machine canalso be printed.

The electrical machine can be assembled by assembling a front end cap tothe housing. The three stators (main, exciter, PMG) can be assembledinto the housing. Current transformers (CTs) can be assembled into thehousing. The rotor (with rotating rectifier, etc.) can be assembled intothe stator. The rear end cap can be added to the housing, andappropriate electrical connections can be added.

In accordance with example aspects of the present disclosure, variouscomponents may be formed or “printed” using an additive-manufacturingprocess, such as a 3-D printing process. The use of such a process mayallow the components to be formed integrally, as a single monolithiccomponent, or as any suitable number of sub-components. In particular,the manufacturing process may allow these components to be integrallyformed and include a variety of features not possible when using priormanufacturing methods.

As used herein, the terms “additively manufactured” or “additivemanufacturing techniques or processes” refer generally to manufacturingprocesses wherein successive layers of material(s) are provided on eachother to “build-up”, layer-by-layer, a three-dimensional component. Insome embodiments, the successive layers generally fuse together to forma monolithic component which may have a variety of integralsub-components. Although additive manufacturing technology is describedherein as providing for the fabrication of complex objects by buildingobjects point-by-point, layer-by-layer, typically in a verticaldirection, other methods of fabrication are possible and within thescope of the present disclosure. For example, although the discussionherein refers to the addition of material to form successive layers, oneskilled in the art will appreciate that the methods and structuresdisclosed herein may be practiced with any additive manufacturingtechnique or manufacturing technology. For example, embodiments of thepresent invention may use layer-additive processes, layer-subtractiveprocesses, or hybrid processes.

Suitable additive manufacturing techniques in accordance with thepresent disclosure include, for example, Fused Deposition Modeling(FDM), Selective Laser Sintering (SLS), 3D printing such as by inkjetsand laserjets, Sterolithography (SLA), Direct Selective Laser Sintering(DSLS), Electron Beam Sintering (EBS), Electron Beam Melting (EBM),Laser Engineered Net Shaping (LENS), Laser Net Shape Manufacturing(LNSM), Direct Metal Deposition (DMD), Digital Light Processing (DLP),Direct Metal Laser Sintering (DMLS), and other known processes.

The additive manufacturing processes described herein may be used forforming components using any suitable material. More specifically,according to example embodiments, the components described herein may beformed in part, in whole, or in some combination of materials includingbut not limited to pure metals, cobalt alloys, iron-cobalt vanadiumalloy, nickel alloys, chrome alloys, titanium, titanium alloys,magnesium, magnesium alloys, aluminum, aluminum alloys, austenite alloyssuch as nickel-chromium-based superalloys (e.g., those available underthe name Inconel® available from Special Metals Corporation), and metalceramic composite (e.g., an aluminum SiC matrix).

One skilled in the art will appreciate that a variety of materials andmethods for bonding those materials may be used and are contemplated aswithin the scope of the present disclosure. As used herein, referencesto “fusing” may refer to any suitable process for creating a bondedlayer of any of the above materials. For example, if the material ispowdered metal, the bond may be formed by a melting process. One skilledin the art will appreciate that other methods of fusing materials tomake a component by additive manufacturing are possible, and thepresently disclosed subject matter may be practiced with those methods.

In addition, the additive manufacturing process disclosed herein allowsa single component to be formed from multiple materials. Thus, thecomponents described herein may be formed from any suitable mixtures ofthe above materials. For example, a component may include multiplelayers, segments, or parts that are formed using different materials,processes, and/or on different additive manufacturing machines. In thismanner, components may be constructed which have different materials andmaterial properties for meeting the demands of any particularapplication.

An example additive manufacturing or printing process will now bedescribed. Additive manufacturing processes fabricate components usingthree-dimensional (3D) information, for example a three-dimensionalcomputer model, of the component. Accordingly, a three-dimensionaldesign model of the component may be defined prior to manufacturing. Inthis regard, a model or prototype of the component may be scanned todetermine the three-dimensional information of the component. As anotherexample, a model of the component may be constructed using a suitablecomputer aided design (CAD) program to define the three-dimensionaldesign model of the component.

The design model may include 3D numeric coordinates of the entireconfiguration of the component including both external and internalsurfaces of the component. For example, the design model may define thebody, the component base, the surface, any surface features such asirregularities or datum features, as well as internal passageways,openings, support structures, etc. In one example embodiment, thethree-dimensional design model is converted into a plurality of slicesor segments, e.g., along a central (e.g., vertical) axis of thecomponent or any other suitable axis. Each slice may define atwo-dimensional (2D) cross section of the component for a predeterminedheight of the slice. The plurality of successive 2D cross-sectionalslices together form the 3D component. The component is then “built-up”slice-by-slice, or layer-by-layer, until finished.

In this manner, the components described herein may be fabricated usingthe additive process, or more specifically each layer is successivelyformed, e.g., by fusing sintering metal powder using laser energy orheat. For example, a particular type of additive manufacturing processmay use an energy beam, for example, an electron beam or electromagneticradiation such as a laser beam, to sinter or melt a powder material. Anysuitable laser and laser parameters may be used, includingconsiderations with respect to power, laser beam spot size, and scanningvelocity. The build material may be formed by any suitable powder ormaterial selected for enhanced strength, durability, and useful life,particularly at high temperatures.

Each successive layer may be, for example, between about 0.25 mil and200 mil, although the thickness may be selected based on any number ofparameters and may be any suitable size according to alternativeembodiments. Therefore, utilizing the additive formation methodsdescribed above, the components described herein may have cross sectionsas thin as one thickness of an associated powder layer, e.g., 10 mil,utilized during the additive formation process.

In addition, utilizing an additive process, the surface finish andfeatures of the components may vary as needed depending on theapplication. For example, the surface finish may be adjusted (e.g., madesmoother or rougher) by selecting appropriate laser parameters duringthe additive process. A rougher finish may be achieved by increasinglaser scan speed or a thickness of the powder layer, and a smootherfinish may be achieved by decreasing laser scan speed or the thicknessof the powder layer. The scanning pattern and/or laser power can also bechanged to change the surface finish in a selected area of thecomponents.

Notably, in example embodiments, several features of the componentsdescribed herein were previously not possible due to manufacturingrestraints. However, the present disclosure advantageously utilizescurrent advances in additive manufacturing techniques to develop exampleembodiments of such components generally in accordance with the presentdisclosure. Additive manufacturing does provide a variety ofmanufacturing advantages, including ease of manufacturing, reduced cost,greater accuracy, etc.

In this regard, utilizing additive manufacturing methods, evenmulti-part components may be formed as a single piece of continuousmetal, and may thus include fewer sub-components and/or joints comparedto prior designs. The integral formation of these multi-part componentsthrough additive manufacturing may advantageously improve the overallassembly process. For example, the integral formation reduces the numberof separate parts that must be assembled, thus reducing associated timeand overall assembly costs. Additionally, existing issues with, forexample, leakage, joint quality between separate parts, and overallperformance may advantageously be reduced.

Also, the additive manufacturing methods described above enable muchmore complex and intricate shapes and contours of the componentsdescribed herein. For example, such components may include thin crosssectional layers and novel surface features. All of these features maybe relatively complex and intricate for avoiding detection and/orimpeding counterfeiting by a third party. In addition, the additivemanufacturing process enables the manufacture of a single componenthaving different materials such that different portions of the componentmay exhibit different performance characteristics. The successive,additive nature of the manufacturing process enables the construction ofthese features.

FIG. 1 depicts a flow diagram of an example method 100 of manufacturingan electrical machine according to example embodiments of the presentdisclosure. FIG. 1 depicts steps performed in a particular order forpurposes of illustration and discussion. Those of ordinary skill in theart, using the disclosures provided herein, will understand that thesteps of any of the methods disclosed herein can be adapted, expanded,include sub-steps, modified, omitted, performed simultaneously, and/orrearranged in various ways without deviating from the scope of thepresent disclosure.

At (102), the method 100 can include printing a stator assembly for theelectrical machine. Example techniques for printing stator componentswill be discussed with reference to FIGS. 2-8.

At (104), the method 400 can include printing a rotor assembly for theelectrical machine. Example techniques for printing rotor componentswill be discussed with reference to FIGS. 9-16;

At (106), the method 100 can include printing a housing for theelectrical machine. Example techniques for printing housing componentswill be discussed with reference to FIG. 25;

At (108), the method 100 can include assembling the various componentsto form the electrical machine. One example method for assemblingvarious components to form an example electrical machine will bediscussed with reference to FIGS. 26 and 27.

FIG. 2 depicts a flow diagram of an example method 200 for printing astator assembly of an electrical machine according to exampleembodiments of the present disclosure. As discussed above, FIG. 2depicts steps performed in a particular order for purposes ofillustration and discussion. Those of ordinary skill in the art, usingthe disclosures provided herein, will understand that the steps of anyof the methods disclosed herein can be adapted, expanded, includesub-steps, modified, omitted, performed simultaneously, and/orrearranged in various ways without deviating from the scope of thepresent disclosure.

At (202), the method 200 can include printing a first lamination sheetof a stator core as a layer. The desired slot skew and/or slot wedge canbe designed and printed as part of the lamination sheet of the statorcore.

FIG. 3 depicts a plan view of an example lamination sheet 222 of astator core 220 (shown in FIG. 4) printed according to example aspectsof the present disclosure. The lamination sheet 222 can have a thicknessin the range of, for instance, about 5 mil to about 20 mil, such asabout 10 mil. The lamination sheet 222 can be printed, for instance, asan iron-cobalt-vanadium soft magnetic alloy (e.g. Hiperco50 Alloy). Asshown, the desired slot skew 228 and slot wedge 226 can be designed fora stator core 220 and can be printed as part of the lamination sheet222.

In some embodiments, the bottom lamination sheet 222 of the stator core220 can be printed with a first projection 229 as depicted in FIG. 4. Inparticular, the first projection 229 can be a tab. As will be discussedbelow in more detail, the first projection 229 can contact a secondprojection 236 (FIG. 5) that is printed as part of a stator winding. Inthis way, the first projection 229 and the second projection 236 canassist with coupling the stator winding with the stator core 220.

At (204), the method 200 can include printing at least one spacer forbeing disposed the lamination sheets. FIG. 3 depicts example spacers 224for being disposed between the lamination sheets 222 of the stator core220. The spacers 224 can have a thickness that is small enough to makeeddy current losses negligible. In some embodiments, the spacers 224 canhave a thickness that is less than a thickness of the lamination sheet222. In some embodiments, the thickness of the spacers 224 can be in therange of, for instance, 0.25 mil to about 1 mil, such as about 0.5 mil.In alternative embodiments, a thickness of the spacers can be equal to 0mil. In this way, harmonic frequencies in the rotor can be minimized.

The spacers 224 can be printed of any suitable material. In someembodiments, the spacers 224 are formed from a different materialrelative to the lamination sheet 222. For instance, the spacers 224 canbe formed from a material having a higher resistivity relative to thematerial of the lamination sheet 220. In some embodiments, the materialfor the spacers 224 can be a nickel alloy, such as Incone1718 or othermaterial.

Referring back to FIG. 2, printing the lamination sheet (202) andprinting the spacers (204) can be repeated until the stator core isfinished (206) or reaches a desired size (e.g., height). An examplestator core 220 printed according to example embodiments of the presentdisclosure is depicted in FIG. 4.

At (208), the method 200 can include printing a first part of a statorwinding. For instance, bottom end turns 237 (FIG. 5) and coils (notshown) for the slots defined by the stator core can be printed as partof the first part of the stator winding. In some embodiments, the secondprojection can assist with positioning of the first part of the statorwinding relative to the stator core. The second projection can providespace between phases, space between coils and slots, space between endturns and core face, etc. As mentioned above, the first projection andthe second projection can contact one another when the first part of thestator winding is coupled to the stator core 220. FIG. 5 depicts anexample first part 232 of the stator winding 230 according to exampleembodiments of the present disclosure.

At (210), the method 200 can include coupling the first part of thestator winding to the stator core. FIG. 6 depicts the first part 232 ofthe stator winding 230 being coupled to the stator core 220 according toexample aspects of the present disclosure. More specifically, FIG. 7 isa close-up view of FIG. 6 and depicts the first projection 229contacting the second projection 236.

Once the first part of the stator winding is coupled to the stator core,the method 200 can include printing a second part of the stator windingonto the first part of the stator winding as shown at (212) of FIG. 2.In this way, the stator assembly can be formed. FIG. 8 depicts anexample stator assembly 250 that includes the second part 234 of thestator winding 230 printed onto the first part 232 of the stator winding230 after the first part 232 of the stator winding 230 has beenassembled with the stator core 220. As shown, the second part 232 of thestator winding 230 can include top end turns 239.

Referring to (214) of FIG. 2, the method 200 includes applying a varnishor epoxy to the stator assembly. In example embodiments, applying thevarnish or epoxy can include potting the varnish or epoxy onto thestator assembly. Alternatively, applying the varnish or epoxy caninclude electrophoretically depositing the varnish or epoxy onto thestator assembly.

After applying the varnish or epoxy at (214), the method 200 caninclude, at (216), removing the first projection from the stator coreand removing the second projection from the first part of the statorwinding. In addition, spaces can be filled with insulation and/orelectrical leads can be attached.

In some embodiments, wire for the stator assembly and/or othercomponents of the electrical machine can be printed according to exampleaspects of the present disclosure. The wire for the windings and othercomponents can be printed in solid wire or hollow wire. In someembodiments, litz wire or hollow wire can be printed.

FIG. 9 depicts a flow diagram of an example method 300 for printing arotor assembly of an electrical machine according to example embodimentsof the present disclosure. As discussed above, FIG. 9 depicts stepsperformed in a particular order for purposes of illustration anddiscussion. Those of ordinary skill in the art, using the disclosuresprovided herein, will understand that the steps of any of the methodsdisclosed herein can be adapted, expanded, include sub-steps, modified,omitted, performed simultaneously, and/or rearranged in various wayswithout deviating from the scope of the present disclosure.

At (302), the method 300 can include printing a first or bottom portionof a rotor shaft layer by layer until it reaches a desired height. FIG.10 depicts the first portion 322 of the rotor shaft 320 printedaccording to example embodiments of the present disclosure. The firstportion of the rotor shaft can be printed of any suitable material. Forexample, in some embodiments, the first portion of the rotor shaft canbe printed of a steel alloy, such as a #4340 steel alloy containing, forinstance, nickel, chromium, and molybdenum. Other suitable materials canbe used without deviating from the scope of the present disclosure.

At (304), the method 300 can include printing a lamination sheet of arotor core as a layer. Desired features of the rotor core can be printedas part of the lamination sheet. For instance, features associated withone or more cooling tubes for the rotor core can be printed as part ofthe lamination sheet. In some embodiments, a shaft section for the rotorshaft passing through the rotor core can be printed as part of thelamination sheet. Alternative or additionally, a first projection 339(FIG. 12) can be printed as part of the lamination sheet. As will bediscussed below in more detail, the first projection can contact asecond projection that is printed as part of a first part of a rotorwinding. More specifically, the first projection can contact the secondprojection when coupling the first part of the rotor winding to therotor core of the rotor assembly. In this way, positioning of the firstpart of the rotor winding relative to the rotor core can be controlled.

FIG. 11 depicts an example lamination sheet 332 of a rotor core printedaccording to example aspects of the present disclosure. The laminationsheet 332 can have a thickness in the range of, for instance, about 5mil to about 20 mil, such as about 10 mil. The lamination sheet 332 canbe printed using, for instance, as an iron-cobalt-vanadium soft magneticalloy (e.g. Hiperco50 Alloy). As shown, cooling tubes 335 can be printedas part of the lamination sheet 332. The cooling tubes 335 can beprinted of the same material as the lamination sheet 332. For instance,the cooling tubes 335 can be printed as an iron-cobalt-vanadium softmagnetic alloy (e.g. Hiperco50 Alloy). In some embodiments, a portion ofthe rotor shaft 320 can also be printed as part of the lamination sheet.The portion of the rotor shaft 320 can be printed using the same or adifferent material than the lamination sheet 332

At (306), the method 300 can include printing spacers for being disposedbetween the lamination sheets of the rotor core. FIG. 11 depicts examplespacers 334 for being disposed between the lamination sheets 332 of therotor core. In some embodiments, the spacers 334 can have a thicknessthat is less than a thickness of the lamination sheet 332. In someembodiments, the thickness of the spacers 334 can be in the range of,for instance, 0.25 mil to about 1 mil, such as about 0.5 mil. Thespacers 334 can be printed using any suitable material. In someembodiments, the spacers 334 are printed using the same material as thelamination sheet 332. For instance, the spacers 334 can be printed as aniron-cobalt-vanadium soft magnetic alloy (e.g. Hiperco50 Alloy). In someembodiments, the shaft portion of the rotor core 330 can be printedwithout spacers.

Referring back to FIG. 9, printing the lamination sheet at (304) andprinting the spacers at (306) can be repeated as necessary until therotor core is finished (308) or reaches a desired size (e.g., height).An example rotor core 330 printed according to example embodiments ofthe present disclosure is depicted in FIG. 10.

Once the rotor core is finished, the method 300 can include at (310)printing a second or bottom portion of the rotor shaft layer by layeruntil it reaches a desired height. FIG. 12 depicts an example secondportion 324 of a rotor shaft 320 printed according to exampleembodiments of the present disclosure. The second portion of the rotorshaft can be printed of any suitable material. For example, in someembodiments, the second portion 324 of the rotor shaft 320 can beprinted of a steel alloy, such as a #4340 steel alloy containing, forinstance, nickel, chromium, and molybdenum. Other suitable materials canbe used without deviating from the scope of the present disclosure.

Referring to (312) of FIG. 9, the method 300 can include printing afirst part of the rotor winding. As mentioned above, the first part ofthe rotor winding can include a second projection 346 (FIG. 13). Inparticular, the second projection 346 can be printed as part of thefirst part of the rotor winding. FIG. 13 depicts the first part 342 ofthe rotor winding 340 printed according to example embodiments of thepresent disclosure. As shown, bottom end turns 347 can be printed aspart of the first part 342 of the rotor winding 340.

Referring to (314) of FIG. 9, the method 300 can include coupling thefirst part of the rotor winding to the rotor core. FIG. 14 depicts thefirst part 342 of the rotor winding 340 being coupled to the rotor core330 according to example aspects of the present disclosure. When thefirst part 342 of the rotor winding 340 is coupled to the rotor core330, the first projection 339 contacts the second projection 346 asdepicted in FIG. 15. In this way, a position of the first part 342 ofthe rotor winding 340 relative to the rotor core 330 can be controlled.

Once the first part of the rotor winding is coupled to the rotor core,the method 300 can include printing, at (316) a second part of the rotorwinding onto the first part of the rotor winding 340 to form the rotorassembly. FIG. 16 depicts a second part 344 of the rotor winding 340printed onto the first part 342 of the rotor winding 340 after couplingthe first part 342 of the rotor winding 340 to the rotor core 330. Asshown, the second part 344 of the rotor winding 340 can include top endturns 349.

Referring to FIG. 9 at (318), the method 300 can include applying avarnish or epoxy to the rotor assembly. For instance, the rotor assemblycan be varnished using a varnish or an epoxy. Alternatively oradditionally, the epoxy can be potted. Still further, the varnish orepoxy can be electrophoretically deposited onto the rotor assembly.After applying the varnish or epoxy to the rotor assembly, the method300 can include, at (319), removing the first projection from the rotorcore and the second projection from the first part of the rotor winding.In addition, spaces can be filled with insulation and/or electricalleads can be attached. In some embodiments, as shown in FIG. 16,accessories such as end caps 352, retaining rings 354, and/or coolingcomponents 356 can be assembled to the rotor core 330 to complete therotor assembly 350.

Variations and modifications can be made to the rotor assembly 350without deviating from the scope of the present disclosure. Forinstance, as shown in FIG. 17, wet cavity oil spray nozzles 351 can beprinted as part of the rotor core 330 for use in wet cavity electricalmachines.

FIGS. 19 through 24 depict another example method 400 for manufacturinga rotor assembly for an electrical machine. At (402), the method 400 caninclude printing a rotor core 360. The rotor core 360 can be printed ofany suitable material. For instance, the rotor core 360 can be printedusing an iron-cobalt-vanadium soft magnetic alloy (e.g. Hiperco50Alloy).

At (404), the method 400 can include printing at least one damp bar 370.The at least one damp bar 370 can be printed from any suitable material.In addition, the method 400 can include, at (406), coupling the at leastone damp bar 370 to the rotor core 330. In example embodiments, couplingthe at least one damp bar 370 to the rotor core 330 comprises insertingthe at least one damp bar 370 into one of a plurality of slots 362defined by the rotor core 360.

At (408), the method 400 can include printing a damp ring 372. The dampring 372 can be printed from any suitable material. In addition, themethod 400 can include, at (410) coupling the damp ring 372 to the rotorcore 360. In example embodiments, the damp ring 372 can be positioned ona first end 364 of the rotor core 360. In alternative embodiments,however, the damp ring 372 can be positioned on a second end 366 of therotor core 360. In particular, the second end 366 can be spaced apartfrom the first end 364 along a length L of the rotor core 360.

At (412), the method 400 can include printing a first part 382 of arotor shaft 380 onto the first end 364 of the rotor core 360. Inaddition, the method 400 can include, at (414), printing a second part384 of the rotor shaft 380 onto the second end 366 of the rotor core 360to form the rotor assembly.

Referring now to FIG. 25, example embodiments of the present disclosureare directed to printing a housing for the electrical machine to houseand support the various components of the electrical machine, such as astator assembly printed according to example embodiments of the presentdisclosure and/or the rotor assembly printed according to exampleembodiments of the present disclosure.

FIG. 25 depicts an example housing 500 printed according to exampleembodiments of the present disclosure. As shown, the housing 500 definesa cavity 510. In particular, the cavity 510 is configured to housevarious components of an electrical machine, such as one or morestators, one or more rotors, CTs, rotating rectifiers, etc. In exampleembodiments, the housing 500 can be printed layer by layer perpendicularto a centerline 506 extending through each bearing center of a pair ofbearing centers 508.

Furthermore, since additive manufacturing is used, the housing 500 canbe printed with a cooling jacket 502 so that the housing 500 and thecooling jacket 502 can be integral with one another. Integrally printingthe housing 500 with the cooling jacket 502 can allow for theelimination of various components (e.g., seals) that would typically bea part of the electrical machine housing. In addition, the coolingjacket 502 can define one or more passages for a fluid (e.g., oil) topass therethrough. In particular, the one or more passages can includean oil circuit or a sump. The housing 500 can include other componentsfor housing the various components, such as a structure 504 for housinga stator assembly for the electrical machine.

In example embodiments, the cooling jacket 502 can be printedcontemporaneously with at least a portion of the housing 500.

Once the housing 500 has been printed according to example embodimentsof the present disclosure, the method can include assembling variouscomponents to form an electrical machine. For instance, the statorassembly, rotor assembly, and other components can be assembled with thehousing 500 to form an electrical machine.

FIGS. 26 and 27 depict a flow diagram of an example method formanufacturing an electrical machine including a main stator, an exciterstator, and a PMG stator for use in, for instance, aircraft or otheravionic applications. FIG. 26 depicts a flow diagram of an examplemethod (600) for manufacturing various components (e.g., statorassemblies, rotor assemblies, etc.) for use in the electrical machine.At (602), the method 600 can include printing main, exciter, and PMGstator assemblies for the electrical machine. The stator assemblies canbe printed, for instance, using the method discussed with reference toFIG. 2.

At (604), the method 600 can include applying a varnish or epoxy to themain, exciter, and PMG stator assemblies. For instance, the statorassemblies can be varnished using a varnish or an epoxy. Alternativelyor additionally, the stator assemblies can be potted (e.g., with epoxy)or deposited. After applying the varnish or epoxy to the statorassemblies, a first projection, such as the first projection 229discussed above with reference to FIG. 4, can be removed from a statorcore for each of the stator assemblies. In addition, a secondprojection, such as the second projection 236 discussed above withreference to FIG. 5, can be removed from a first part of a statorwinding for each of the stator assemblies. After removing the first andsecond projections, spaces can be filled with insulation and/orelectrical leads can be attached.

At (606), the method can include printing a main rotor assembly. Themain rotor assembly can be printed, for instance, using the methoddiscussed with reference to FIG. 8. Alternatively, the main rotorassembly can be printed, for instance, using the method discussed abovewith reference to FIG. 24.

At (608), a varnish or epoxy can be applied to the main rotor assembly.After applying the varnish or epoxy to the rotor assembly, a firstprojection, such as the first projection 339 discussed above withreference to FIG. 12, can be removed from a rotor core of the main rotorassembly. In addition, a second projection, such as the secondprojection 346 discussed above with reference to FIG. 13, can be removedfrom a first part of a rotor winding of the main rotor assembly. Afterremoving the first and second projections, spaces can be filled withinsulation and/or electrical leads can be attached.

At (610), the method can include printing the exciter and PMG rotorassemblies. The exciter rotor assembly can be printed for instance,using the method discussed with reference to FIG. 9. The PMG rotor canbe printed according to example aspects with the present disclosure withslots for permanent magnets.

At (612), the method can include assembling the rotor components. Forinstance, the exciter and PMG rotor can be assembled together. Variouscomponents associated with the rotor(s) can be assembled, such as arotating rectifier, bearings, seals, etc.

At (614), the exciter and PMG rotor assemblies can be finished. Forinstance, varnish or epoxy can be applied to each of the exciter and PMGrotor assemblies; spaces can be filled with insulation; and electricalleads can be attached.

At (616), the method can include printing a housing for the statorassemblies and rotor assemblies associated with the electrical machine.In some embodiments, the housing can have an integrated cooling jacketand other components for housing the stator assemblies and rotorassemblies. End caps, retaining rings, and other components of theelectrical machine can also be printed.

FIG. 27 depicts a flow diagram of an example method 650 of assemblingthe various printed components together to form an electrical machineaccording to example embodiments of the present disclosure. At (652),the method 650 can include assembling or coupling a front end cap to thehousing. The main, exciter, and PMG stators can then be assembled intothe housing at (654).

At (656), the method 650 can include assembling the CTs. The main rotorassembly as well as the exciter rotor and PMG rotor assembly can beassembled into the housing (658). The rear end cap can be assembled ontothe housing (660). At (662), the electrical machine can be finished. Forinstance, appropriate electrical connections can be included in theelectrical machine. In this way, an electrical machine can bemanufactured using 3D printing technology that provides many advantagesover typical methods of manufacturing electrical machines.

Variations and modifications can be made to the example embodimentsdisclosed herein. For instance, in some embodiments, an electricalmachine can be printed as a stand-alone unit. The electrical machine canbe printed according to example embodiments of the present disclosureand can include various features. For instance, a housing 710 for anelectrical machine 700 can be printed as part of the lamination sheetswhen printing a stator core according to example embodiments of thepresent disclosure. For example, as shown in FIGS. 28 and 29, at leastone air cooling fin 732 can be printed as part of the housing 710 thatis printed when printing the stator core 220. Alternatively oradditionally, at least one mounting ear 734 can be printed as part ofthe housing 710. In example embodiments, the at least one air coolingfin 732 and/or the mounting ear 734 can be printed when printing thestator core 220. More specifically, the air cooling fin 732 and/or themounting ear 734 can be printed as part of the stator core 220. Inexample embodiments, printing the mounting ear 734 can occurcontemporaneously with printing the housing 710. More specifically, themounting ear 734 can be integral with the housing 710. Alternatively oradditionally, at least one end cap 736 can be printed as part of thehousing 710. Furthermore, when manufacturing the housing 710, the endcap 736 can be coupled to the housing 710 via the mounting ear 734. Whenthe end cap 736 is coupled to the housing 710 via the mounting ear 734,a cavity 740 defined by the housing 710 can be enclosed. In exampleembodiments, a first end cap can be coupled to the housing 710 via afirst pair of mounting ears positioned at a first end of the housing710. In addition, a second end cap can be coupled to the housing 710 viaa second pair of mounting ears positioned at a second end of the housing710. In particular, the second end can be spaced apart from the firstend along a length of the housing 710. When the stator assemblies androtor assemblies are coupled to one another and disposed within thecavity 740, the end cap 736 can, in effect, seal the stator and rotorassemblies from an external environment.

FIGS. 30 through 32 depict another example embodiment of an electricalmachine that can be printed according to example embodiments of thepresent disclosure. For example, a housing 810 for an electrical machine800 can include a cooling jacket 830. Alternatively or additionally, thehousing 810 can include at least one mounting ear 834. Alternatively oradditionally, the housing 810 can include at least one end cap 836. Morespecifically, the cooling jacket 830, mounting ear 834 and/or the endcap 836 can be printed as part of the stator core 220. In this way, thecooling jacket 830, mounting ear 834 and/or the end cap 836 can beintegral with the stator core 220. In some embodiments, featuresassociated with the cooling jacket 830 and/or the mounting ear 834 canbe printed as part of the lamination sheets when printing the statorcore 220. For example, printing the cooling jacket 830 can includeprinting the cooling jacket 830 so that the cooling jacket 830 definesone or more passages for a fluid to pass therethrough. In particular,the one or more passages can include an oil circuit for oil to passtherethrough. Alternatively or additionally, the one or more passagescan include a sump for oil to pass therethrough. It should beappreciated, however, that any suitable fluid can be passed through theoil circuit and the sump.

As shown, the housing 810 defines a cavity 840 configured to accommodateat least the stator core 220 and the rotor core 330. In exampleembodiments, the cavity 840 can be in fluid communication with the oneor more wet cavity spray nozzles 351 defined by the rotor core 330. Inthis way, a fluid exiting the wet cavity spray nozzle(s) 351 can enterthe cavity 840. As such, the printed electrical machine depicted in FIG.31 is a wet cavity electrical machine. In contrast, the printedelectrical machine depicted in FIG. 30 is a dry cavity electricalmachine, because the rotor core 330 does not include one or more wetcavity spray nozzles 351.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method for manufacturing an electrical machine,the method comprising: printing a stator core; printing a first part ofa stator winding; coupling the first part of the stator winding to thestator core; printing a second part of the stator winding onto the firstpart of the stator winding to form a stator assembly; printing a firstpart of a rotor shaft; printing a rotor core onto the first part of therotor shaft; printing a second part of the rotor shaft onto the rotorcore; printing a first part of a rotor winding; coupling the first partof the rotor winding to the rotor core; and printing a second part ofthe rotor winding onto the first part of the rotor winding to form arotor assembly, wherein coupling the first part of the stator winding tothe stator core precedes printing the second part of the stator windingonto the first part of the stator winding, and wherein coupling thefirst part of the rotor winding to the rotor core precedes printing thesecond part of the rotor winding onto the first part of the rotorwinding.
 2. The method of claim 1, further comprising printing a housingdefining a cavity.
 3. The method of claim 1, wherein printing the statorcore comprises printing a first projection, wherein printing the firstpart of the stator winding comprises printing a second projection, andwherein the first projection contacts the second projection when thefirst part of the stator winding is coupled to the stator core.
 4. Themethod of claim 3, further comprising: applying a varnish or epoxy tothe stator assembly; removing the first projection from the stator coreafter applying the varnish or epoxy; and removing the second projectionfrom the first part of the stator winding after applying the varnish orepoxy.
 5. The method of claim 4, wherein applying the varnish or epoxyprecedes printing the first part of the rotor shaft.
 6. The method ofclaim 4, wherein removing the first projection from the stator coreprecedes printing the first part of the rotor shaft, and whereinremoving the second projection from the first part of the stator windingprecedes printing the first part of the rotor shaft.
 7. The method ofclaim 1, wherein printing the rotor core comprises printing a firstprojection, wherein printing the first part of the rotor windingcomprises printing a second projection, and wherein the first projectioncontacts the second projection when the first part of the rotor windingis coupled to the rotor core.
 8. The method of claim 7, furthercomprising: applying a varnish or epoxy to the rotor assembly; removingthe first projection from the rotor core after applying the varnish orepoxy; and removing the second projection from the first part of therotor winding after applying the varnish or epoxy.
 9. The method ofclaim 1, wherein printing the first part of the stator winding comprisesprinting first end turns and a plurality of coils, and wherein printingthe second part of the stator winding comprises printing second endturns.
 10. The method of claim 9, wherein printing the plurality ofcoils comprises printing at least one wire.
 11. A method formanufacturing an electrical machine, the method comprising: printing, bya three-dimensional (3D) printing process, a stator core; printing, bythe 3D printing process, a first part of a stator winding; coupling thefirst part of the stator winding to the stator core; after coupling thefirst part of the stator winding to the stator core, printing, by the 3Dprinting process, a second part of the stator winding onto the firstpart of the stator winding to form a stator assembly; printing, by the3D printing process, a rotor core; printing, by the 3D printing process,a first part of a rotor shaft onto a first end of the rotor core;printing, by the 3D printing process, a second part of the rotor shaftonto a second end of the rotor core; printing, by the 3D printingprocess, a first part of a rotor winding; coupling the first part of therotor winding to the rotor core; and after coupling the first part ofthe rotor winding to the rotor core, printing, by the 3D printingprocess, a second part of the rotor winding onto the first part of therotor winding to form a rotor assembly, wherein the 3D printing processcomprises fusing metal using laser energy or heat.
 12. The method ofclaim 11, further comprising printing, by the 3D printing process, ahousing defining a cavity.
 13. The method of claim 11, wherein printingthe stator core comprises printing, by the 3D printing process, a firstprojection, wherein printing the first part of the stator windingcomprises printing, by the 3D printing process, a second projection, andwherein the first projection contacts the second projection whencoupling the first part of the stator winding to the stator core. 14.The method of claim 13, further comprising: applying a varnish or epoxyto the stator assembly; removing the first projection from the statorcore after applying the varnish or epoxy; and removing the secondprojection from the first part of the stator winding after applying thevarnish or epoxy.
 15. The method of claim 14, wherein applying thevarnish or epoxy occurs before printing the rotor core.
 16. The methodof claim 14, wherein removing the first projection from the stator coreprecedes printing the rotor core, and wherein removing the secondprojection from the first part of the stator winding precedes printingthe rotor core.
 17. The method of claim 11, wherein printing the rotorcore comprises: printing, by the 3D printing process, at least one dampbar; and printing, by the 3D printing process, a damp ring afterprinting the at least one damp bar.
 18. The method of claim 11, whereinprinting the first part of the stator winding comprises printing firstend turns and a plurality of coils, and wherein printing the second partof the stator winding comprises printing second end turns.
 19. Themethod of claim 18, wherein coupling the first part of the statorwinding to the stator core comprises inserting each coil of theplurality of coils into one slot of a plurality of slots defined by thestator core.
 20. The method of claim 18, wherein printing the pluralityof coils comprises printing at least one wire.